In a first-of-its-kind study, scientists in Europe have found that pregnancy causes structural brain changes in women. These changes could last about two years. Findings of the study were published Monday in the journal Nature Neuroscience. When scientists compared brain scans of 25 first-time moms before and after pregnancy, they found differences in 11 areas of their brains.

Pregnancy causes brain changes
Image Credit: Greyerbaby / Pixabay

Pregnancy alters the size of structure of some brain parts

Elseline Hoekzema, the lead author of the study, said pregnancy reduces gray matter in some parts of a woman’s brain. It helps the mother bond with her baby and prepare for motherhood. The study was conducted by researchers at the Autonomous University of Barcelona and Leiden University. Scientists said the level of brain changes observed during pregnancy were similar to those seen during adolescence.

The study revealed that pregnancy alters the size and structure of parts of the brain involved in social interactions and feelings to other people, which are also known as the “Theory-of-Mind” tasks. It helps mothers become more aware of potential social threats, recognize the needs of their baby, and get more attached to the baby. The brain scans were taken before women became pregnant, soon after childbirth, and two years later.

No changes in the brains of fathers

Scientists compared these women’s brain scans with those of 17 first-time fathers and 20 women who had never conceived. The loss of gray matter was seen only in pregnant women. No changes were noticed in the first-time fathers when their brains were scanned before and after their partners’ pregnancy.

The more pronounced the structural changes, the higher mothers scored on emotional attachment to their babies. Computers were able to identify women who had been pregnant simply by analyzing their brain scans. In one experiment, scientists monitored brain activity while women were shown photos of their own babies and other babies.

Loss of gray matter not a bad thing

The areas of the brain that lit up when women saw pictures of their own babies matched the areas where gray matter had reduced during pregnancy. Elseline Hoekzema said the loss of gray matter is not necessarily a bad thing. Scientists are uncertain precisely what was reduced in size: synapses, neurons, parts of the circulatory system, or other brain cells.

The brain changes took place during pregnancy rather than after childbirth. More research is needed to confirm whether the loss of gray matter is indeed linked to improved mothering skills and the “Theory of Mind.” Hoekzema believes the changes result from an extreme surge in sex hormones during nine months of pregnancy. During pregnancy, estrogen level in women is greater than at any point in the rest of their lives.